The invention relates to systems for locating and/or identifying animals or objects within an operating environment created through use of a control center, transceivers (repeaters) strategically located to reduce signal distortion or loss, and xe2x80x9ctagsxe2x80x9d which are affixed to the animals and objects. The systems are designed to support a subscriber base and to detect and/or record movement, a lack of movement, the direction and rate of movement of the tagged animals or objects and the projected direction and rate of tag movement. The systems can also provide subscribers with sensor inputs, e.g., pulse and temperature. Tag size, power consumption and cost have limited the utilization of such systems.
The use of tags utilizing a microcomputer and transceiver repeaters and a control unit to inventory moving and moveable items is thoroughly explained by F. W. Anders, et al, U.S. Pat. No. 4,656,463. This patent teaches a variety of types of location and identification tags and their circuitry, operating modules, frequencies and programming. The use of some types of tag encryption, chip programming and reprogramming and sensors is also explained.
B. F. Rice, U.S. Pat. No. 5,452,328, teaches a location system utilizing multicode spectrum spreading techniques.
Joseph Hoshens, U.S. Pat. No. 5,461,390, teaches a system designed to track stalkers, stalkees, abducted or stolen animals or objects to which tags are attached. Police mobile units, which can be vectored to potential trouble spots, or to respond to emergencies.
The system is based on a cell phone-type network. Polling signals are sent to transceivers (repeaters) in each cell which then broadcast the polling signals to each of the tags. Each of the polled tags then interrogates a unit of a global positioning system to obtain its coordinate position. This information is then broadcast to the control center via the repeaters. Alternately, the tags can transmit signals which are triangulated by the control center data processor to obtain the tag location. The coordinates are then, in the case of a stalker, compared with the spatial coordinates of locations, permitted to the stalker or the stalker""s spatial relationship to the stalkee. If the stalker is in a nonpermitted area, or too close to the stalkee, police are then notified of the fact. In the case of an abducted child, the presence of the child in a location outside a designated area would trigger a notification of the police. Alternately, the child can trigger an abduction-in-progress alarm.
M. S. Singer, et al, U.S. Pat. No. 5,483,163, teach a child monitoring system where the tag is polled or activated by the wearer. The polled tag then transmits an identification/location signal to the network repeaters. The repeaters then transmit the signal to the control centers to enable the child, potential molesters, etc., to be located in a signal strength analysis of the inputs from the control center and/or repeaters.
Later, S. J. Heiser, et al, U.S. Pat. No. 5,748,148 is quite detailed. It teaches systems specifically designed to reduce signal distortion and to extend tag battery life. The tags respond to a polling enquiry at a response amplitude which is selected to reach only nearby relays and/or the control center to calculate the tag, including the coordinates of the broadcasting report location.
J. C. Otto, et al, U.S. Pat. No. 5,870,029, teaches the location of objects or persons, e.g., a person under house arrest, within designated areas. Effectively speaking, a police car acting as a mobile transceiver is dispatched to apprehend the fugitive when he or she is outside the designated areas. A geo-positioning system is utilized to provide the necessary spatial coordinates. The mobile transceiver utilizes signal strength, ranging Doppler effects, phase shifting, radio direction, time difference of signals arrived and radio frequencing ranging for determining the location of the tagged individual or object.
S. A. Parl, et al, U.S. Pat. No. 5,883,598, teach a location system designed to augment cellular phone or paging systems. Each tag transmits locating signals to one or more repeaters within the cell areas. A base station relay (repeater) within the cell areas receives the locating signals and transmits to the control center signals indicative of the phase and amplitude of each locating signal as received. These data provide the basis for calculating the tag(s) position(s).
The tag-based systems of this invention utilize a monitoring and control center (center), repeaters and tags. The systems differ from those of the prior art in that commercial chips, chip sets, and software are combined with custom (application) software and provide a unique center and smaller, cheaper and more versatile tags. The repeater and center location data are embedded in tag memory, e.g., permanent (ROM) and/or recordable memory, e.g. EEPROM and EAPROM. The tag function is readily augmented through the use of embedded of plug-in sensors which communicate with tags by rf or light communication.